In conventional methods of wellbore drilling, tubular casing is installed in the wellbore at selected depth intervals. Each new casing to be installed must pass through the previously installed casing, therefore the new casing must be of smaller diameter than the previously installed casing. As a result of such procedure, the available internal diameter of the wellbore for fluid production becomes smaller with depth. For very deep wells, or for wells in which casing is to be installed at relatively short intervals, such conventional casing scheme may render the well uneconomical. In view thereof it has been proposed to radially expand casing/liner sections after installation at the desired depth.
EP-A-1044316 discloses a method whereby a first tubular element is installed in the wellbore, and a second tubular element is installed in the wellbore so that an upper part of the second tubular element extends into a lower part of the first tubular element so as to form an overlapping portion of the tubular elements. The upper part of the second tubular element is then radially expanded against the first tubular element such that as a result thereof said lower part of the first tubular element is radially expanded.
A drawback of the known method is that the expansion forces needed to expand the lower part of the first tubular element generally are extremely high.
It is therefore an object of the invention to provide an improved method of installing a tubular assembly in a wellbore, which overcomes the drawback of the known method.